14367-54-5Relevant academic research and scientific papers
Enantioselective hydrogenation of α,β-unsaturated carboxylic acid over cinchonidine-modified Pd nanoparticles confined in carbon nanotubes
Guan, Zaihong,Lu, Shengmei,Li, Can
, p. 1 - 5 (2014)
We report the enantioselective hydrogenation of α,β-unsaturated acid catalyzed by Pd nanoparticles in carbon nanotubes (CNTs) taking the advantage of the channels as nanoreactors. The Pd nanocatalyst inside the channels of CNTs shows higher activity and e
Model Studies on the Enzyme-Regulated Stereodivergent Cascade Passerini Reaction
Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard,Samsonowicz-Górski, Jan,Wilk, Monika
supporting information, p. 4161 - 4165 (2021/08/24)
The synthesis of chiral α-acyloxy carboxamides containing two stereogenic centers continues to be a challenging field of organic chemistry. Herein, we have proposed and proved the feasibility of an enzyme regulated-cascade reaction, which using the same substrates enables the formation of individual stereoisomers of α-acyloxy carboxamides with up to 99 % ee. The access to the individual stereoisomeric products has been achieved by a combination of the enzymatic kinetic resolution of racemic vinyl esters, subsequent Passerini reaction, and enzymatic kinetic resolution of formed α-acyloxy carboxamides. The presented studies are promising in exploratory proof-of-concept of enzyme-controlled stereodivergent cascade to form an important class of chiral compounds for medicinal chemistry.
Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H2 Cleavage
Chirik, Paul J.,Shevlin, Michael,Zhong, Hongyu
supporting information, (2020/03/13)
The asymmetric hydrogenation of α,β-unsaturated carboxylic acids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri-, and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylic acids including Naproxen, (S)-Flurbiprofen, and a d-DOPA precursor. Turnover numbers of up to 200 were routinely obtained. Compatibility with common organic functional groups was observed with the reduced cobalt(0) precatalysts, and protic solvents such as methanol and isopropanol were identified as optimal. A series of bis(phosphine) cobalt(II) bis(pivalate) complexes, which bear structural similarity to state-of-the-art ruthenium(II) catalysts, were synthesized, characterized, and proved catalytically competent. X-band EPR experiments revealed bis(phosphine)cobalt(II) bis(carboxylate)s were generated in catalytic reactions and were identified as catalyst resting states. Isolation and characterization of a cobalt(II)-substrate complex from a stoichiometric reaction suggests that alkene insertion into the cobalt hydride occurred in the presence of free carboxylic acid, producing the same alkane enantiomer as that from the catalytic reaction. Deuterium labeling studies established homolytic H2 (or D2) activation by Co(0) and cis addition of H2 (or D2) across alkene double bonds, reminiscent of rhodium(I) catalysts but distinct from ruthenium(II) and nickel(II) carboxylates that operate by heterolytic H2 cleavage pathways.
Electrocatalytic asymmetric hydrogenation of α,β-unsaturated acids in a PEM reactor with cinchona-modified palladium catalysts
Atobe, Mahito,Fukazawa, Atsushi,Hashimoto, Yasushi,Sato, Yasushi,Tanaka, Kenta
, (2020/04/28)
We have developed an electrocatalytic asymmetric hydrogenation reaction using a proton-exchange membrane (PEM) reactor that employs a polymer electrolyte fuel cell and industrial electrolysis technologies. Reasonable enantioselectivities and excellent current efficiencies were obtained in the asymmetric hydrogenation of α-phenylcinnamic acid under mild conditions without adding a supporting electrolyte. The current density was crucial to achieving the improved results observed.
Deracemizing α-Branched Carboxylic Acids by Catalytic Asymmetric Protonation of Bis-Silyl Ketene Acetals with Water or Methanol
Mandrelli, Francesca,Blond, Aurélie,James, Thomas,Kim, Hyejin,List, Benjamin
, p. 11479 - 11482 (2019/07/18)
We report a highly enantioselective catalytic protonation of bis-silyl ketene acetals. Our method delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.
A chiral double tooth nitrogen phosphine ligand and its asymmetric catalytic reaction in the application of the (by machine translation)
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Paragraph 0067-0068, (2017/08/29)
The invention relates to a nitrogen phosphine double tooth ligand and its asymmetric catalytic reaction in the application. In the present invention discloses a novel double-phosphine - oxazoline ligand is a containing biphenyl shaft not stable structure of the ligand, and the successful application of α - methyl cinnamic acid and its derivatives of the high-efficiency high-selective asymmetric hydrogenation and its similar reaction. The type ligand the synthetic route is simple, low cost, stable in air, to the carbon-carbon double bond of the asymmetric hydrogenation reaction demonstrate the high activity and high selectivity, has wide industrial applications. (by machine translation)
Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids
Yang, Shuang,Che, Wen,Wu, Hui-Ling,Zhu, Shou-Fei,Zhou, Qi-Lin
, p. 1977 - 1980 (2017/03/09)
We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF?) counterion, which is necessary for stabilizing cationic Crabtree-type catalysts. Another advantage of the neutral iridium catalysts is that they have high stability and have a long lifetime in air. The new iridium catalysts with chiral spiro phosphine-carboxy ligands exhibit unprecedented high enantioselectivity (up to 99.4% ee) in the asymmetric hydrogenations of various unsaturated carboxylic acids, particularly for 3-alkyl-3-methylenepropionic acids, which are challenging substrates for other chiral catalysts.
Novel iridium complex of spirophosphine-carboxylic acid, preparation method and application thereof
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Paragraph 0081-0085, (2017/05/20)
The invention relates to an iridium complex of spirophosphine-carboxylic acid, a preparation method and application thereof. The iridium complex of spirophosphine-carboxylic acid is a compound with a structure shown as formula (I), wherein n=0-3; and the values of R1, R2, R3, R4, R5, R6 and R7 are defined as claim 1. Substituted 7-carboxyl-7'-diarylphosphino-1, 1'-spirobiindane is taken as the ligand to from carboxylic acid anion under the action of alkali, and then complexation with an iridium precursor is carried out to obtain different iridium/spirophosphine-carboxylic acid complexes. The iridium complex of spirophosphine-carboxylic acid provided by the invention can catalyze the asymmetric hydrogenation reaction of a variety of unsaturated carboxylic acids, and show high activity and enantioselectivity, thus having good industrialization prospects. (formula (I)).
Asymmetric Hydrogenation of α-Substituted Acrylic Acids Catalyzed by a Ruthenocenyl Phosphino-oxazoline-Ruthenium Complex
Li, Jing,Shen, Jiefeng,Xia, Chao,Wang, Yanzhao,Liu, Delong,Zhang, Wanbin
supporting information, p. 2122 - 2125 (2016/06/01)
Asymmetric hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX-Ru as a chiral catalyst under 5 bar H2, affording the corresponding chiral α-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to construct bioactive chiral molecules. The asymmetric protocol was successfully applied to an asymmetric synthesis of dihydroartemisinic acid, a key intermediate required for the industrial synthesis of the antimalarial drug artemisinin.
Synthesis of Enantiomerically Enriched 2-Hydroxymethylalkanoic Acids by Oxidative Desymmetrisation of Achiral 1,3-Diols Mediated by Acetobacter aceti
Brenna, Elisabetta,Cannavale, Flavia,Crotti, Michele,De Vitis, Valerio,Gatti, Francesco G.,Migliazza, Gaia,Molinari, Francesco,Parmeggiani, Fabio,Romano, Diego,Santangelo, Sara
, p. 3796 - 3803 (2016/12/24)
The stereoselective desymmetrisation of achiral 2-alkyl-1,3-diols is performed by oxidation of one of the two enantiotopic primary alcohol moieties by means of Acetobacter aceti MIM 2000/28 to afford the corresponding chiral 2-hydroxymethyl alkanoic acids (up to 94 % ee). The procedure, carried out in aqueous medium under mild conditions of pH, temperature and pressure, contributes to enlarge the portfolio of enzymatic oxidations available to organic chemists for the development of sustainable manufacturing processes.
